This invention relates a key having a gripping portion made of synthetic resin.
Keys having a gripping portion made of synthetic resin have been frequently utilized since any color of synthetic resin can be used, and the synthetic resin therefor has good electrical insulation properties.
A conventional key having a gripping portion made of synthetic resin consists of a key body having a blade portion wherein key serrations are formed at the side thereof, and a gripping portion is attached and fixed at the insertion portion of the corresponding key body. The thickness of the gripping portion is two to four times the thickness of the blade portion, because it is necessary to mold the insertion portion of the key body so as to cover the insertion portion thereof with a fixed thickness when the gripping portion is composed of synthetic resin.
Therefore, in the event that a plurality of keys according to the conventional examples are attached to a key ring or the like, a problem occurs in that they become bulky in volume.
Hence, the applicant has proposed a key having a gripping portion made of synthetic resin, which consists of a key body furnished with a blade portion on which key serrations are formed, as shown in the U.S. patent application Ser. No. 442,816, and an insertion portion is integrally connected to the corresponding blade portion, having a thickness which is thinner than the corresponding blade portion. The corresponding gripping portion is inserted and fixed in the corresponding insertion portion, having a thickness in the range of 0.9 through 1.3 times that of the blade portion.
However, since the insertion portion of the key body is made thinner than the thickness of the blade portion of the corresponding key body, if a large torque is applied to the insertion portion, or if the gripping portion is bent with the blade portion inserted in the key slot, there may occur a problem wherein the junction portion between the insertion portion and the blade portion, where a stage is formed, is damaged.
The present invention has been proposed, taking these problems into consideration. It is therefore an object of the invention to provide a key having a thin gripping portion made of synthetic resin, which is not bulky in use and in which the strength of the key has been further increased.